The deadline for the UK to formally exit the EEA is looming, and with it the possibility of legal uncertainty.

The UK government has until March 29 to invoke Article 127 of the 1994 European Economic Area (EEA) Agreement, ending the UK's membership of the broader Single Market, which includes non-EU countries Norway, Iceland and Liechtenstein.

Although the government has repeatedly insisted Brexit means the UK is leaving the Single Market, many argue that without triggering Article 127 we will still be members, and consequently bound by obligations that the 2016 referendum vote appeared to go against.

In other words, the UK may remain a part of the Single Market unless the clause has been triggered.

Downing Street and some EU officials have argued that the UK will automatically leave the EEA, saying we cannot be in this union and simultaneously outside the EU and Efta.

From a legal perspective, though, it has been argued that Article 127 is distinct from Article 50, because the former is outside EU law. As a result, if the government wishes to leave the two bodies, it must invoke this second clause.

Some parliamentarians have been enthusiastic proponents of remaining a part of Efta-EEA as a soft Brexit option, although it is not seen as likely to be adopted by the government at this stage.